Liquid crystal display apparatus are currently a popular choice for flat-panel display apparatuses where an array substrate serves as an important role. When manufacturing a liquid crystal display apparatus, testing the array substrate is necessary for improving the yield. Generally, the array substrate is combined with a color film substrate to form a display panel, and then, a testing signal is supplied to the array substrate. Whether the array substrate is effective can be determined based on whether the display panel works normally or not. However, the current testing methods are not satisfying because voltages on common electrodes are unstable.